Implants for holding together portions of a bone to support bone healing are known. For instance, FIG. 11 shows an example of a conventional implant. The implant, commercially available from DePuy Synthes®, having a place of business in West Chester, Pa., is used to hold together fractured portions of a sacrum. The implant can include one or more rod assemblies 200, each having a rod 201 that extends through first and second opposed portions 12 and 11 of the ilium, respectively, that are positioned on opposed medial-lateral sides of the sacrum S. The rod can be threaded, and configured to threadedly receive respective first and second nuts 202 and 204 at its opposed first and second ends. The first and second nuts 202 and 204 can be threaded onto the rod 201, and compressed against the first and second portions 12 and 11 of the ilium so as to provide a compressive force to a fractured sacrum S. The implant can further include a first washer 206 disposed between the first nut 202 and the first portion 12 of the ilium, and a second washer 208 disposed between the second nut 204 and the second portion 11 of the ilium.
FIG. 12 shows another conventional implant that uses compression to hold bone portions together during a healing process. The implant illustrated in FIG. 12 is used for syndesmosis fixation, and is commercially available under the product name TightRope® from Arthrex, Inc., having a place of business in Napes, Fla. The implant illustrated in FIG. 12 includes a bone plate 210 and a button 212 that are disposed on opposite sides of bone. The bone plate 210 is anchored to the bone using one or more screws 214, and a suture 216 is drawn through the bone from the button 212 to the bone plate 212 and fastened to the bone plate 212 to provide compression to the bone.
Yet another conventional implant shown in FIG. 13 uses compression to support a healing process of the acromioclavicular (AC) joint. The implant illustrated in FIG. 13 is the MINAR® system, commercially available from Karl Storz GmbH & Co. KG, having a place of business in Berlin, Germany. The implant of FIG. 13 can include first and second buttons 218 and 220 that are disposed on opposed surfaces of the clavicle 217 and the coracoid process 219, respectively, and a suture 221 that extends through the first button 218, through the AC joint and wraps around the second button through first and second apertures, respectively, and is drawn again through the AC joint and through the first button 218. The suture 221 can be fastened to the first button such that the suture 221 provides compression between the first and second buttons 218 and 220, and thus provides compression between the clavicle and the coracoid process.
A problem common to all these systems is that once implanted and without additional surgery it is complicated to adjust the implant to, for example, maintain the compressive force supporting the healing process.